Folded dipole and mounting assembly

ABSTRACT

THE ALIGNED OPPOSED LEGS OF TBES BENT INTO SIMILAR ELONGATED U-SHAPES ARE SECURED MECHANICALLY IN ALIGNMENTS AS A FOLDED DIPOLE BY A FEED CONNECTION FITTING BETWEEN ONE ALIGNED LEG PAIR, AND BY BOLTING OF THE OTHER PAIR TO A NARROW SEAT ON THE EDGE OF A SHEET METAL BRACKET, HAVING SPACED PARALLEL FOLDED SIDES TERMINATING IN INWARDLY OFFSET FLANGES CURVED FOR SEATED, ROTATIONALLY ADJUSTABLE, SECUREMENT ON A CYLINDRICAL MAST BY HOSE CLAMP   TYPE CLAMPING STRAPS. THE FEED CABLE, PASSING THROUGH A GROMMETED BRACKET APERTURE, IS MECHANICALLY AND ELECTRICALLY CONNECTED WITH THE FITTING, AND THEREBY TO THE TUBULAR MEMBERS, IN A DESIGN FACILITATING FABRICATION AND ASSEMBLY, ESPECIALLY OF A PLURALITY OF ASSEMBLIES ON A MAST.

Feb. 16, 1971 J. SCHULLER FOLDED DIPOLE AND MOUNTING ASSEMBLY Filed Aug. 12, 19 68 lll F IG?) INVENTOR.

JOHN SCHULLER BY ATTORNEYS United States Patent O U.S. Cl. 343803 9 Claims ABSTRACT OF THE DISCLOSURE The aligned opposed legs of tubes bent into similar elongated U-shapes are secured mechanically in alignment as a folded dipole by a feed connection fitting between one aligned leg pair, and by bolting of the other pair to a narrow seat on the edge of a sheet metal bracket, having spaced parallel folded sides terminating in inwardly offset flanges curved for seated, rotationally adjustable, securement on a cylindrical mast by hose clamp type clamping straps. The feed cable, passing through a grommeted bracket aperture, is mechanically and electrically connected with the fitting, and thereby to the tubular members, in a design facilitating fabrication and assembly, especially of a plurality of assemblies on a mast.

Various forms of folded dipole antenna elements and support means for securing them on a mast, for example, rotationally in adjustable positions for changed directivity or pattern of radiation, are known to the prior art; but these have suffered various disadvantages arising from relative complexity or cost of bracket or support means whereby the dipole element is secured to a mast, or in complexity of the structure or in fabrication of the mechanical components or electrical connection of a feed cable to the element, or, even where a relatively simple bent tubular single dipole element is used, in the fabrication of such element.

It is the general object of the present invention to pro vide a dipole and mounting assembly useful for transmitting, receiving and transceiver antennas whereby one or more of such disadvantages of the prior art are overcome.

Another object of the invention is the provision of a form of folded dipole element and mounting bracket assembly, which is relatively simple and of lower cost in construction and fabrication, in contrast with prior art assemblies of comparable performance, ruggedness and durability, for similar application, especially in communications service.

A more particular object is the provision of a folded dipole and mounting assembly design of simplified form adapted for easy mounting and parallel-feed connection of a plurality thereof in a vertical array on a mast structnre, and thereafter ready adjustment, particularly in rotational sense about the mast for attainment of a desired radiation pattern or directivity in vertical arrays.

Other objects and advantages will appear from the following description and the drawings wherein:

FIG. 1 is a schematic or outline representation of an antenna mast mounting in vertical array a plurality of dipole elements as a typical environment of use of the invention;

FIG. 2 is a side elevation of a single dipole element and mounting assembly embodying the present invention, as secured on a section of a vertical mast; and

FIG. 3 is a fragmentary enlarged view in axial section through a feed cable connecting fitting portion of the dipole with the feed cable end portion bearing couplnig connecting elements separated from the connecting fitting.

As a typical environment for use of the invention FIG.

3,564,554 Patented Feb. 16, 1971 1 represents schematically an antenna mast M of cylindrically tubular form having disposed thereon in vertical array four similar vertical folded dipole and mounting assemblies, designated by the general reference characters Dl, D2, D3, D4 with preferred vertical offset therebetween on the order of 0.9 to 1.0 wave length. The dotted line representation in conjunction with the solid line representation shows the possibility of positions which may desirably be obtainable by angular, i.e., rotational, shifting of the individual units about the mast.

It is to be understood that the invention herein described is applicable for transmitting, receiving or transceiver antennas; and the terminology feed cable is not restrictive to transmitting applications, but includes as well receiver antenna applications; and also that reference to wave length or frequency comprehends the range of wave lengths or frequencies for which a given antenna may be suitable, or the mid-range value.

The folded dipole element and mount assembly of the invention is shown in one embodiment in FIG. 2, including as principal components an elongated bracket B; a cable connecting fitting F for feed line or cable C; two generally similar, elongated U-shaped, bent cylindrically tubular metal members T-l, T-Z, mechanically and electrically joined into a folded dipole element by a cable connecting fitting F securing the opposed outboard leg ends of the members in aligned relation and by securement of the other opposed leg ends in aligned spaced relation on bracket B; and a pair of hose clamp type straps H, passed through inner edge portions of the bracket embracing the mast tube in screw clamp tightened relation to secure the bracket and hence the assembly to the mast.

The conductive bracket B is conveniently and preferably fabricated of sheet metal by well known blanking out and forming techniques, as an integral structure providing a straight narrow outboard longitudinal edge 11, preferably transversely concave complementary to and to form a seat for the tubular members T-1, T-2; from the center and respective ends of which edge end struts 12a and center struts 12b extend towards the mast defining on each side similarly shaped parallel spaced and offset open sides 12 terminating in longitudinally offset inwardly reflected flanges 13 forming mast-engaging opposite longitudinal edge portions, preferably concavely shaped complementary to the mast circumferential curvature.

The strap portions of the hose clamp devices H pass through respective slots (not shown) in the flange portions 13 adjacent the antenna mast.

The dipole feed line or cable portion C, here shown as descending along and secured to the mast by band or tape means as at 15, as for the lowermost assemblies D2, or D-4, of dipole pairs parallel fed in a cascading feed from a main cable (not detailed), is readily led through the open bracket structure and a grommeted opening 16 centrally located in the bracket tube seating edge between the bolted tube ends to be anchored in a mechanical and electrical connection to the dipole element at the hereinafter described fitting F.

In addition to mechanical support and connection to each other of the bent elongated tubular members T-1 and T-2 afforded by pairs of screws or bolts S passed through and securing respective leg ends 011 the seating bracket edge 11, the fitting F also provides a further mechanical connection of the aligned outboard ends to each other as shown more clearly in the detailed FIG. 3. Obviously screws or bolth S may either be engaged in threaded holes in the edge 11, or extend through such holes for nut securement.

The tubular members T-1 and T-2 are each formed of like tubular stock, here cylindrical, bent into generally similar U-shapes; but as here shown though the leg lengths of the top member T-l are substantially equal, in the lower member T-2 the outboard leg is slightly shorter than the inner, merely as dictated by the particular dimensions of the structure shown for a body portion of fitting F.

In the fitting body 20, the upper end of a vertical longitudinal through-bore is female threaded to receive the lower male threaded end of a conductive or metal stud plug 21 press-fitted into the outboard leg lower end of the member T-1; while, in its lower counter-bored femalethreaded end there is threaded an insulated conductive plug press-fitted into the upper end of the free outboard leg of the member T2, comprising an insulating plug 22 with a rigidly secured round nut-like conductive or metal plug element 24. A connector stud or pin 23 extending through and partially threaded in a central bore of plug 22 projects downwardly in stud-like fashion to mount the plug nut 24.

The outer circumferences of plugs 21 and the plug nut 24 are preferably serrated, with longitudinal grooves, for example, in accordance with standard practice for this type of press-fits. Thus the fitting F provides a rigid aligning connection between the threaded plug-carrying ends of the two tubular members. Also a protective sleeve of insulating plastic material 25 extending downwardly from the end of the body 20 over the projecting portion of plug 22 and the upper end of the tubular element T-2 protects the lower, insulated plug and the abutment joint thereof with T2 against moisture and weathering; and for like purposes, preferably each of the bracket-secured ends of the tubing is closed as at 26 with a plastic plug.

The body 20 further has a side bore perpendicularly intersecting the vertical bore and female threaded to accept the inner male threaded end of a cable anchoring adapter sleeve 27 having its center elongated bore endthreaded to accept anchor sleeve nut 28. The upwardly projecting unthreaded part of the rod 23 coaxially disposed in the through-bore has a transverse or diametric bore 23a in coaxial alignment with the side bore axis for securement, in the manner hereinafter detailed, of the inner conductor 33 of cable C.

For mechanical and electrical connection of the cable C in the fitting, in addition to the coupling nut 28, initially slideable on the outer insulating cable covering, successively inward thereof there are provided a pair of washers 29 with an interposed ring gasket 30, and a ring 31 end-tapered in shape complementary to, and received in, the tapered end recess inward of the female threads of 27. Thus with the exposed cable inner conductor 33 inserted and secured in 23, the backwardly flared exposed braided layer outer conductor 34 is engaged and held between the conical female and male portions of 27 and ring 31 by axial force communicated from the sleeve nut 28. The latter force further serves to distort the gasket into compressing circumferential engagement with the outer sheath of the cable C to anchor the same against withdrawal through nut 28.

The exposed inner end of conductor 33 may be secured in various ways, as by a set screw 35 threaded axially into the end of 23; or with a bit of solder pre-loaded into an end aperture communicating with 23a, with subsequent heating applied thereto; either the screw driving or soldering done through the open upper end of body 20 while the top member T-1 and its plug are not yet installed.

For assembly of a mast M with a plurality of dipoles, assume the brackets B, the feed cable harness, and the U-shaped tubes completed; that each tube T-l has a plug press-fitted therein to appropriate position as a sub-assembly, and so also that plug 22 is similarly press-fitted in each T2 with rod 23, plug 24 and sleeve 25 in place as further sub-assemblies. Then in final assembly of each dipole onto the mast, the respective bracket B is clamped in place, the fitting F screwed into place on the insulated plug end of T2, and the latter bolted into position on the bracket with C extending through the latter. The insertion of the end of a respective cable C carrying the anchor assembly into 27, the soldered or set-screw connection into the end of 23a and the screwing of the anchoring assembly into 27 are next completed. The top sub-assembly of T-1 is then screwed into place in the fitting F, and finally the free inner leg of T1 is bolted into position on the bracket already positioned on the mast. The same operations are then completed for each dipole and mounting assembly.

From the above description it can be seen that there are decided advantages in the provision of the folded dipole element through the two separate members T-1, T2, so readily secured in the final assembly as above described, but having the great advantages of the simplicity and lower cost of forming the two separate half portions in comparison with forming a folded dipole tube out of a singular tubular element.

Further there is provided a relatively simple bracket structure easily fabricated at low cost by known sheet metal fabricating techniques in contrast with more costly castings or weldments. Also by the fitting F and associated structure a good mechanical and electrical connection between the components is thus readily attained including a good weather-tight joint.

Also with respect to lightning each dipole element is well grounded through the bracket to the metal mast.

I claim:

1. A folded dipole and mounting bracket assembly comprising:

a pair of elongated U-shaped tubular members having similarly spaced respective parallel legs with the legs of one member disposed in opposed aligned endspaced relation with those of the other member;

a narrow elongated bracket;

means securing the ends of one aligned pair of said legs on a longitudinal edge of the bracket and thereby securing them in mechanically aligned and electrically connected relation to each other;

dipole feed line connecting fitting means independent of said bracket and interposed between and mechanically connecting and securing the ends of the other pair of aligned said legs to each other in the aligned relation;

said connecting fitting means adapted to electrically connect respective conductors of a feed line to the last said ends of the members;

said bracket as an integral structure providing as said longitudinal edge an elongated seat for the ends of the first said aligned leg pair,

flange means forming an opposite longitudinal edge adapted to engage a longitudinal portion of a mast,

and intermediate spacing structure joining the seat and flange means; and

means through the flange means adapted to secure the bracket and thereby the entire assembly to the mast.

2. An assembly as described in claim 1, with the last said means being clamping strap means, and with said connecting fitting means disposed outboard of said bracket.

3. The assembly as described in claim 1 wherein said bracket comprises a sheet metal stamping having an elongated longitudinally straight edge transversely concave complementary to a portion of the tubular circumference of said members; integral spacing strut means on respective sides of and extending away from the seat in respective parallel planes, each said strut means comprising a strut element at a respective one end of the bracket, a second strut element originating near midlength of the seat, and a joining strut parallel to the seat; i

said flange means provided by respective flanges extending inward from the joining struts in longitudinally offset relation, and curved for accommodation to a round tubular mast.

'4. An assembly as described in claim 1, wherein said seat portion, between seated ends of said tubular members, is centrally apertured and insulator-grommeted, whereby a dipole feed line may be led through and partially supported in the bracket to terminate in said fitting means.

5. A folded dipole and mounting bracket assembly comprising:

a pair of elongated U-shaped tubular members having similarly spaced respective parallel legs with the legs of one member disposed in opposed aligned endspaced relation with those of the other member;

a narrow elongated bracket;

means securing the ends of one aligned pair of said legs on a longitudinal edge of the bracket and thereby securing them in mechanically aligned and electrically connected relation to each other;

dipole feed line connecting fitting means interposed between and mechanically connecting and securing the ends of the other pair of aligned said legs to each other in the aligned relation;

said connecting fitting means adapted to electrically connect respective conductors of a feed line to the last said ends of the members and including a conductive body threaded at opposite ends,

a first said tubular member having on one leg thereof threaded means cooperating with one threaded end of the body to secure the one leg thereto and the other leg thereof apertured to receive therethrough fastener means for securing it to said longitudinal edge of the bracket,

the second said tubular member having a leg thereof apertured for fastener means securing the same on said edge in alignment with the corresponding leg of the first member and having insulating threaded means on the other leg thereof cooperating with the other threaded end of said body to secure the last said other leg on the body and thereby to, and in alignment with, the corresponding leg of the first member; and

means on the body for anchoring the end of a twoconductor feed line with electrical connection of one conductor to said body and of the second conductor to the end of said second member secured to said body.

6. A folded dipole and mounting bracket assembly comprising:

a pair of elongated U-shaped tubular members having similarly spaced respective parallel legs with the legs of one member disposed in opposed aligned end-spaced relation with those of the other member;

a narrow elongated bracket;

means securing the ends of one aligned pair of said legs on a longitudinal edge of the bracket and thereby securing them in mechanically aligned and electrically connected relation to each other; and

dipole feed line connecting fitting means interposed between and mechanically connecting and securing the ends of the other pair of aligned said legs to each other in the aligned relation;

said connecting fitting means adapted to electrically connect respective conductors of a feed line to the last said ends of the members and including a conductive hollow body having at one end a first conductive cylindrical plug adapted to receive thereon in press-fitted relation a leg of a first of said members and to electrically connect the body thereto, and, at the other end, a second similar plug insulated from and supported by the body in alignment with the first plug and adapted similarly to receive the corresponding end of the second tubular member in pressfitted relation, the second said plug having an insulated connector for a feed line conductor to be electrically connected to the last said tubular member, and anchor means on the body for anchoring the end of a two-conductor feed line with electrical connection of one conductor to said body and the second conductor to the said insulated connector. 7. An assembly as described in claim 6, wherein: said body is threaded at one end to receive a cooperatively threaded first said plug, and also threaded at the other end;

said body having a longitudinal through-bore and a side bore in perpendicular intersecting relation to the through-bore;

the said first member having one leg thereof apertured to receive therethrough fastener means for securing it to said longitudinal edge as a seat and, as a subassembly, the first plug press-fitted in the other leg thereof;

said second plug being insulated from the body by an interposed insulating plug in threaded engagement with the other threaded end of the body and the second plug secured to the insulating plug by said connector,

said connector having an end located in said through bore transversely apertured in alignment with the side bore axis whereby it may receive and secure the end of the said second conductor coaxially disposed in the side bore, and further carrying means for securing the second conductor.

8. The assembly as described in claim 7, wherein the said second tubular member has one leg thereof apertured for fastener means securing the same in said seat and, as a sub-assembly, has said second plug press-fitted in the other leg thereof.

9. The assembly of claim 8 in combination with a flexible coaxial cable as the feed line having a center conductor as the said second conductor and a surrounding braided conductor; said anchoring means including, on the cable within the side bore, a ring holding an exposed end portion of the braided conductor conductively in engagement with the body, a cable anchoring annular gasket and a sleeve nut threaded into the side bore compressing the gasket against the ring.

References Cited UNITED STATES PATENTS 2,567,577 9/1951 Pariser 343-803 2,641,703 6/1953 Valach 343803 3,007,167 10/1961 Winegard 343-803 3,299,429 1/ 1967 MOMullin 343-803 ELI LIEB-ERMAN, Primary 'Examiner US. Cl. X.R. 343-880 

